Device could revolutionize computer memory

Emma Woollacott, 21st January 2011

Researchers from North Carolina State University have developed a new device that they say represents a big advance for computer memory, making server farms more energy efficient and allowing computers to start more quickly.

The team has developed a single unified device that can perform both volatile and nonvolatile memory operation and which can be used in the main memory.

Traditionally, slow memory - nonvolatile - devices are used in persistent data storage technologies such as flash drives and can save information for extended periods of time.

Fast memory like DRAM allows computers to operate more quickly, but aren’t able to save data when the computers are turned off.

The NC device, though, can perform both volatile and nonvolatile memory operation.

"Our device is called a double floating-gate field effect transistor (FET). Existing nonvolatile memory used in data storage devices utilizes a single floating gate, which stores charge in the floating gate to signify a 1 or 0 in the device – or one bit of information,"
says Dr Paul Franzon, a professor of electrical and computer engineering.

"By using two floating gates, the device can store a bit in a nonvolatile mode, and/or it can store a bit in a fast, volatile mode – like the normal main memory on your computer."

The double floating-gate FET could allow computers to start immediately. They wouldn’t have to retrieve start-up data from their hard drive, as it would be stored in main memory.

It would also allow 'power proportional computing', says Franzon. For example, web server farms, such as those used by Google, consume an enormous amount of power, even when there are low levels of user activity. This is partly because they can’t turn off the power without affecting main memory.

Franzon says that the device appears to be reliable and could have a 'very long' lifetime, when storing data in the volatile mode.